Research On Aerodynamic Interference And Matching Between Contra Rotating Prop-Fan

To study the influence of the parameters of the counter-rotating prop-fan stage on its aerodynamic performance.First,an eight-bladed prop-fan was generated on the basis of the existing one—SR-3,and performance verification was carried out.Then,based on the 8-blades single-rotating prop-fan,generated a counter-rotating prop-fan,and studied the effects of physical parameters on the performance of the whole and front/rear stages of the counter-rotating prop-fan by the numerical simulation method,the law of inter-stage interference was obtained.Finally,a counter-rotating prop-fan with different diameters of front and rear stages was matched according to the law obtained,and the performance of the counterrotating propeller fan was optimized.Firstly,aerodynamic performance of an 8-blade single-rotor prop-fan at different flight speeds was studied.Then the variation of the aerodynamic performance of the counter-rotating prop-fan and blade load with the number of blades were compared and analyzed when the flight Mach number is 0.80.Found that when the advance ratio remains unchanged,as the number of flying Mach increases,the propulsion efficiency of the prop-fan decreases monotonously,and when Mach 0.8 was reached,the rate of change suddenly increased;the number of blades can also affect the efficiency of propulsion,as the number of blades decreased,the propulsion efficiency gradually increased.However,the pulling force reduced and the blade load increased gradually.Then,the numerical method was used to study the influence of four physical parameters on the aerodynamic performance of the whole counter-rotating prop-fan and its front and rear stages.The four physical parameters were the installation angle of the rear stage,the spacing between the front and rear stages,the number of blades in the rear stages and the diameter of the rear stage.The effects of these four physical parameters on the aerodynamic performance of a rotating propeller fan can be divided into two categories: the front and rear stages spacing and the number of blades can affect the aerodynamic performance of the front and rear stages simultaneously.But on the J-η chart,the position of the peak efficiency point of the latter stage does not move left and right.However,the installation angle of the rear stage and the diameter of the rear stage not only affects the aerodynamic performance of the front and rear stages,but also affects the position of the peak efficiency point on the J-η chart.Finally,according to the rule that the installation angle and the diameter of the rear stage affects the position of the peak point of the latter stage.Aerodynamic matching of a counter rotating prop-fans was taken by adjusting the installation angle of the rear stage,the flow flowing through the rear stage was optimized,and the aerodynamic performance of the counter-rotating prop-fan was enhanced,on the same time,a wider working range was obtained.The following conclusions can be drawn by comparing the calculated results of the single-rotating and counter-rotating prop-fans: Compared with 8-blades single-rotor prop-fan,the 8?6 counterrotating prop-fan with the same blade can produce 5.65%(The relative value was 7.36%)efficiency improvement and 126% pull enhancement,at the same time,93.27% of the torque applied to the fuselage is eliminated.